Sound is filtered by band-pass filters. Full sound range is split into 5, five sonic frequencies are separated from each other.
A low-pass filter is an electronic filter that passes low-frequency signals but attenuates (reduces the amplitude of) signals with frequencies higher than the cutoff frequency. The actual amount of attenuation for each frequency varies from filter to filter. It is sometimes called a high-cut filter, or treble cut filter when used in audio applications. A low-pass filter is the opposite of a high-pass filter. A band-pass filter is a combination of a low-pass and a high-pass.

Five frequencies of sound are converted into five liquid colour paints (ink, water colour, or acrilics).

Open-source schematics are coming soon in pictures, drawings and text.